1. Field of the Disclosure
This disclosure generally relates to apparatus for allowing selective fluid communication between an anesthetic agent container and an anesthetic vaporizer. More particularly, the disclosure relates to an adapter mountable on an anesthetic agent container or on an anesthetic vaporizer for facilitating fluid transfer therebetween.
2. Description of Related Art
During surgical procedures, it often is necessary to anesthetize a patient. One method of delivering anesthetic is in a gaseous form, which is inhaled by the patient. For the safety of the patient and medical personnel, the anesthetic agent is typically transported in liquid form in a suitable container. Known liquid anesthetics include halothane, isoflurane, sevoflurane, desflurane, enflurane, and methoxyflurane. The liquid anesthetic is ultimately dispensed into an anesthetic vaporizer, which mixes the liquid anesthetic agent with a carrier gas, such as oxygen or nitrous oxide, that is inhalable by a patient.
Liquid anesthetics are relatively volatile and can evaporate at room temperature. Before it can be used, the anesthetic agent must be transferred from a first closed environment, e.g., a container or bottle, to a second closed environment, e.g., a vaporizer. In order to transfer the anesthetic, it is well-known to provide a vaporizer fluid port with a valving system that is selectively openable to allow a liquid anesthetic agent to be poured into an internal sump of the vaporizer. Such valving systems are described in U.S. Pat. Nos. 5,381,836 and 5,617,906 to Braatz et al., which are hereby incorporated herein by reference. The valving systems described in Braatz et al. are suitable for use with, for example, commercial desflurane vaporizers. Examples of commercial vaporizers include, but are not limited to the Tec 6 Plus™ of Datex-Ohmeda, Inc. and the D-Vapor™ or Devapor® of Drager Medical AG & Co. KG.
The above patents describe an arrangement in which the anesthetic agent container is provided with an integral or separate adapter with a valving system configured to mate with the vaporizer valving system and allow for selective dispensing of the liquid anesthetic contained therein. To transfer anesthetic agent from the container to the vaporizer, the adapter is inserted into the vaporizer fluid port. As a result of contact between spring-biased portions of the adapter and vaporizer valving systems, fluid communication between the container and vaporizer is opened and fluid exchange can commence.
Some commercial vaporizers include a stop cock or similar means for preventing fluid transfer even after the adapter is engaged by the vaporizer and both valves are opened. In such vaporizers, the stop cock is typically opened by rotating the engaged adapter from a down position to an up position, as described by Braatz et al. In the up position, the stop cock is open and liquid anesthetic agent is allowed to flow from the container into the vaporizer. Thereafter, the adapter is rotated to the down position, if necessary, and removed from the vaporizer fluid port, which automatically closes both valves.
The filling systems of Braatz et al. disclose a sealing surface that is provided toward a free end of the outlet of an adapter associated with an anesthetic agent container. The sealing surface forms a seal with a vaporizer inlet in order to prevent leakage while the adapter is engaged by the vaporizer and one or both of the valves are open. A typical adapter according to Braatz et al. has a tubular spout with a free end that is encircled by an elastomeric o-ring seated in a groove or channel of the spout. The spout is inserted into the fluid port of the vaporizer and the o-ring deforms to form a fluid seal between the outer surface of the spout and an inner surface of the fluid port.
Another characteristic of the filling systems of Braatz et al. is that they use a generally annular projection on the adapter spout as a means for preventing accidental disengagement of an engaged adapter from the vaporizer. Vaporizers requiring rotation of an engaged adapter to open a stop cock typically include a curved slot with a key-hole opening to receive the adapter in the down position. Rotation of the adapter along the slot to the up position causes the slot to grip the projection, thereby preventing disengagement. The projection-slot configuration prevents disengagement of the adapter in any position other than through the key-hole opening of the down position.
As set forth in more detail below, the present disclosure sets forth an improved adapter embodying advantageous alternatives to the sealing and/or retention systems of prior art devices.